This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Although there is evidence that the energy chosen for data collection does not have a great deal of effect in the global quality of the data [Shimizu, Hirata, Hasegawa, Ueno &Yamamoto (2007) J. Synchrotron Radiat. 14 4-10], the effects of local radiation damage at different energies have not been sufficiently studied. Experiments have been undertaken to study the reduction rate of disulfide bridges at 9 and 14.5 keV on lysozyme. The damage to disulfide bridges happens relatively quickly and it is easy to observe and quantify, and the radiation damage mechanism is thought to be the same as for other elements. Preliminary results indicate that the rate of reduction of the disulfide bridges is site depending, with more exposed sites showing an increased rate of decay and there is no apparent difference in the rate of decay at the two energies chosen for the study.